Storage subsystems provide system mass storage incorporating many storage devices. Storage devices usually include hard disk drives, but may include solid-state drives, optical drives, or tape drives. Storage subsystems include within a single storage chassis one or more storage devices, power supplies, and possibly one or more storage controllers, including Redundant Array of inexpensive disks (RAID) controllers.
In order to provide non-stop operation, redundant controllers, power supplies, and/or storage devices are often provided in the storage subsystem. Additionally, such assemblies are generally provided as field replaceable modules or FRUs. Field replaceable modules are packaged individually, in order to facilitate removal and replacement of individual controllers, power supplies, or storage devices. Additionally, such modules are often hot replaceable, and able to be replaced while the storage subsystem is powered up and even actively conducting I/O operations to one or more storage devices. Individual storage devices are commonly packaged within a storage device module consisting of a plastic or sheet metal tray for mounting the storage device and a front bezel incorporating a latching mechanism, and in some cases visual indicators.
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road. Storage enclosures often include spinning devices such as fans or hard disk drives that generate vibrations related to rotation speed and how well motors are balanced. Storage enclosures may additionally be subject to shock events such as when a storage enclosure is dropped onto a hard surface or an outside force strikes the storage enclosure. Both vibration and shock may be transferred at least in part to operating storage devices, resulting in loss of performance and possibly degrading long-term reliability.